Add exhaustive NATS factorial, MQTT/UDP probes, and optimal-config report.

Compares r=1 vs r=3, file vs memory, reconnect tax, and projects three
HP DL360 Gen10 NVMe + 10GbE boxes. Keep NATS; do not switch to MQTT/UDP.

packages/zapier-decisions/STATUS.md

@@ -50,6 +50,19 @@ Measured from LXC **510** (not a nats-* server) against `10.10.10.21–23`.
 
 Live cluster **keeps 8 cores / 16 GiB / max_mem 8G**. Product streams are back on ZFS (tmpfs was study-only).
 
+**Optimal-config study (`20260912T055851Z`):** same 8c/16G cluster on **ZFS**, plus r=1 vs r=3, memory vs file, reconnect tax, UDP echo, MQTT QoS0. Combined report with DL360 Gen10 projection: [HTML](https://zapier.georgelambert.org/packages/zapier-decisions/reports/optimal-config/REPORT.html) · [PDF](https://zapier.georgelambert.org/packages/zapier-decisions/reports/optimal-config/REPORT.pdf).
+
+| Finding | Number |
+|---------|--------|
+| JS file r=3 1p 128 B (8c ZFS) | 14,330 pubs/s |
+| JS file r=1 1p | 18,888 (r=3 costs ~24% on same host) |
+| JS memory r=1 4p | **64,923** (lab JS ceiling) |
+| MQTT QoS0 | 44,862 pubs/s (not durable; ~15× slower than core) |
+| UDP p99 510→511 | 0.363 ms vs NATS ping p99 1.14 ms |
+| Reconnect-per-msg p99 | 1.75 ms vs persistent ping 1.14 ms |
+
+**Do not switch the fabric to MQTT or UDP.** Optimal lab: file r=3 for jobs/archive, memory r=3 optional for events, persistent NATS connections. Metal: 3× DL360 Gen10, local NVMe, 10GbE — projected JS file r=3 **~40–80k** 128 B pubs/s (not measured).
+
 Short tables: [BENCH.md](https://git.georgelambert.org/marchon/verae-nats-cluster/src/branch/main/BENCH.md). Re-run: `bash scripts/bench.sh` on NS1.
 
 | Kind | Load | Result |